1. Field of the Invention
The present invention relates to submersible pumps provided with means to direct fluid to one or more regions adjacent the pump.
2. Description of the Prior Art
The usual submersible pump is designed to be run in a submerged condition and normally becomes overheated when run in an unsubmerged condition, which sometimes results in an explosion, excess current loads or various forms of pump failure. Consequently, in a typical application such as sewage or industrial waste pumping, the sump for the pump must be deep enough to cover the vertically oriented pump with the material to be pumped. Controls are provided to prevent pumping of the material below the upper extremeity of the pump.
Debris, grease and sludge often coat the motor case and insulate it so that it overheats. Such accumulated grease and sludge fail to pass through the pump in the absence of any means to mix such materials with the more liquid portions of the material being pumped.
The usual submersible pumps of the prior art have no means to prevent the accumulation of sand and grit in the motor drive shaft seal area and such pumps are periodically taken out of service for maintenance or replacement of such seals.
Yet another problem with prior art submersible pumps is that there is no relatively inexpensive and simple way to vary the pumping capacity of such pumps to accommodate differential rates of flow of the material being pumped.